This study measured ambient air particulate concentrations by PS-1 and USA samplers at Taichung Harbor (TH) and WuChi traffic (WT) near the Taiwan Strait in central Taiwan during four seasons (March 2004 to January 2005). Measurement results demonstrated that particulate concentrations (TSP, PM2.5-10 and PM2.5) in spring and winter were higher than those in other seasons at WT and TH sampling sites, respectively. Average total suspended particulates (TSP) concentrations (mu gm(-3)) were 149.50 and 106.67 at TH and WT sampling sites, respectively. Average concentrations (mu gm(-3)) Of PM2.5-10 were 28.42 and 22.31 at TH and WT sampling sites, respectively, and average concentrations (mu gm(-3)) Of PM2.5 were 44.77 and 36.81 mu gm(-3) at TH and WT sampling sites, respectively, during sampling periods. Additionally, the highest concentration of metallic elements in TSP, PM2.5-10 and PM2.5 during four seasons was Fe. The two primary components of metallic elements on TSP particulates were Fe (1.151 mu gm(-3)) and Zn (0.793 mu gm(-3)), and Fe (1.303 mu gm(-3)) and Zn (1.081 mu gm(-3)) at the TH and WT sampling sites, respectively. The two primary components of metallic elements in coarse particulates were Fe (0.825 mu gm(-3)) and Mg (0.363 mu gm(-3)), and Fe (0.839 mu gm(-3)) and Mg (0.294 mu gm(-3)) at the TH and WT sampling sites, respectively. Furthermore, the two primary components of metallic elements in fine particulates were Fe (0.253 mu gm(-3)) and Mg (0.167 mu gm(-3)), and Zn (0.491 mu gm(-3)) and Fe (0.382 mu gm(-3)) at TH and WT sampling sites, respectively, during sampling periods.